When coupling the outer conductor of a coaxial line e.g. to the plug socket of a connector, it is known to provide a screw cap which presses the flanged end section of the outer conductor via an intermediate element against the plug socket along an annular contact surface.
The use of such connecting devices is, however, not only limited to connectors (or jacks) but is e.g. required also for connecting two coaxial lines by means of a non-detachable cable coupling, for joining a coaxial line to a transition element etc. If required, these connections can easily be provided in water tight manner.
In coaxial lines of large diameter and operating at an inner overpressure up to several bar, it is known to arrange in the joining area of the outer conductor one or several O-rings within the field-free space beyond the contacting surfaces. In general, the contact surfaces are defined by the end section of the outer conductor which end section is rectangularly flanged outwards and for example by a correspondingly mating flange-like counter surface of a plug socket of a connector. The required pressing force for providing intimate contact is obtained by a screw cap screwed on the plug socket and acting via an intermediate element.
Practice has shown, however, that such a device is disadvantageous especially when the coaxial line has a relatively small diameter. This is because during bending or beading of the end section of the outer conductor in outward direction, cracks or fissures or the like are obtained especially along those areas which are primarily subjected to stretching forces i.e. in the area of the outer side of the end section. These cracks are undesirable as the pressure sealed connection is impaired.
It was thus proposed to provide further sealings e.g. in the area of the screw cap and the plug socket or to inject silicon caoutchouc or the like into the entire connecting device, such a pressure sealed connection is, however, expensive and above all unsuitable when a subsequent adjustment of the electrical length of the coaxial line is required by shortening its mechanical length.